1. Field of the Invention
The present invention relates to plasma display devices and methods of driving the same.
2. Description of the Related Art
In a plasma display device, initialization of display cells is carried out prior to selecting the lighting or non-lighting of each display cell by addressing. In the initialization of display cells, a write operation and an erase operation with respect to the display cells are carried out. In order to suppress deterioration in contrast due to background luminescence, the writing and erasing are carried out by a weak electric discharge. The weak electric discharge in each display cell is generally realized using a slope waveform (graded waveform) of which voltage changes with the lapse of time (for example, see Patent-document 1).
In the conventional plasma display device, the slope waveform is usually generated by supplying an electric power to an electrode of a display cell through a constant current circuit from the power supply capable of outputting an ultimate voltage in the slope waveform. For this reason, a difference between the supply voltage and the electrode voltage is applied to a driving circuit.
As the display panel in a plasma display device becomes large, the load associated with the driving will increase. However, with regards to the time required for reaching the ultimate voltage in the slope waveform, approximately the same time period is required in specification irrespective of the size of the display panel. Accordingly, as the display panel is enlarged, the electric current required for applying the slope waveform will increase, which gives rise to problems, such as a rise in the component temperature due to the increase in the reactive power (loss). Moreover, also in the case where the uniformity of the display cells in the display panel is damaged as the display panel becomes larger, the number of times of applying the slope waveform for initializing the display cells will increase, which causes problems, such as a rise in the component temperature due to an increase in the reactive power (loss).
[Patent document 1] International Publication No. 97/20301